Consumption meters for calculating a consumed quantity of water, heat, cooling, gas or the like, typically have a flow part with a through-going opening that forms a flow passage for a flow of the quantity to be measured and a compartment or housing with a cavity for housing electronic components of the meter. The housing serves to protect the electronic components, such as a measuring circuit for operating the meter, ultrasonic transducers for determining the flow in the flow passage, and additional electronic equipment, such as a calculation circuit for calculating the consumed quantity, a display for displaying a value representing the consumed quantity, a battery for powering the electronic components, a communication module, etc. In particular, the housing serves to protect the electronic components from exposure to the ambient conditions when the consumption meter is placed in wet or moist surroundings.
In a system with automatic meter reading for reporting the consumed quantity, a communication module is used for wireless transmission of the value or a signal representing the consumed quantity. It is of benefit that the signal can be transmitted a certain communication distance i.e. that the consumption meter has a certain communication range. This communication range should preferably be present during the lifetime of the consumption meter.
The desire of protecting the electronic components from ambient exposure and the desire of a certain communication range may be in conflict with each other. One solution of protecting the electronic components is to use an internal antenna, which however may hamper the communication range. Another solution of ensuring a certain communication range is to use an external antenna, this may however either hamper the protection of the electronic components due to the presence of an electric feed through or require a costly solution to provide a housing which protects, and continues to protect, the electronics against exposure from ambient conditions.
In U.S. Pat. No. 5,734,103 a consumption meter instrument is disclosed where a sealing material is used to join together a top and a base of the instrument. A sealed wire entry port is provided where a pair of insulated wires runs through the body of the sealing material. The instrument further comprises a vent which is adapted to be closed after a gas has been either evacuated or introduced into the interior of the housing to reduce moisture within the housing before final sealing.